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Álvarez DMC, Serrano-Muñoz D, Fernández-Pérez JJ, Gómez-Soriano J, Avendaño-Coy J. Effect of percutaneous electrical stimulation with high-frequency alternating currents at 30 kHz on the sensory-motor system. Front Neurosci 2023; 17:1048986. [PMID: 36845426 PMCID: PMC9947497 DOI: 10.3389/fnins.2023.1048986] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 01/24/2023] [Indexed: 02/11/2023] Open
Abstract
Background Unmodulated high-frequency alternating currents (HFAC) are employed for producing peripheral nerves block. HFAC have been applied in humans with frequencies up to 20 kHz, whether transcutaneously, percutaneously, or via surgically-implanted electrodes. The aim of this study was to assess the effect of percutaneous HFAC, applied with ultrasound-guided needles at 30 kHz, on the sensory-motor nerve conduction of healthy volunteers. Methods A parallel, double-blind, randomized clinical trial with a placebo control was conducted. Percutaneous HFAC at 30 kHz or sham stimulation was applied via ultrasound-guided needles in 48 healthy volunteers (n = 24 in each group) for 20 min. The assessed outcome variables were pressure pain threshold (PPT), mechanical detection threshold (MDT), maximal finger flexion strength (MFFS), antidromic sensory nerve action potential (SNAP), hand temperature, and subjective sensations by the participants. The measurements were recorded pre-intervention, during the stimulation (at 15 min), immediately post-intervention (at 20 min), and 15 min after the end of treatment. Results The PPT increased in the active group compared with sham stimulation, both during the intervention [14.7%; 95% confidence interval (CI): 4.4-25.0], immediately post-intervention (16.9%; 95% CI: -7.2-26.5), and 15 min after the end of the stimulation (14.3%; 95% CI: 4.4-24.3) (p < 0.01). The proportion of participants who reported feelings of numbness and heaviness was significantly higher in the active group (46 and 50%, respectively) than in the sham group (8 and 18%, respectively) (p < 0.05). No intergroup differences were observed in the remaining outcome variables. No unexpected adverse effects derived from the electrical stimulation were reported. Conclusion Percutaneous stimulation with HFAC at 30 kHz applied to the median nerve increased the PPT and subjective perception of numbness and heaviness. Future research should evaluate its potential therapeutic effect in people with pain. Clinical trial registration https://clinicaltrials.gov/ct2/show/NCT04884932, identifier NCT04884932.
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Affiliation(s)
- David Martín-Caro Álvarez
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing of Toledo, Universidad de Castilla-La Mancha, Toledo, Spain
| | | | - Juan José Fernández-Pérez
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing of Toledo, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Julio Gómez-Soriano
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing of Toledo, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Juan Avendaño-Coy
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing of Toledo, Universidad de Castilla-La Mancha, Toledo, Spain
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Zhong Y, Zhang X, Beckel J, de Groat WC, Tai C. Intracellular sodium concentration and membrane potential oscillation in axonal conduction block induced by high-frequency biphasic stimulation. J Neural Eng 2022; 19. [PMID: 35850095 PMCID: PMC9355690 DOI: 10.1088/1741-2552/ac81ef] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 07/18/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE A new axonal conduction model was used to analyze the interaction between intracellular sodium concentration and membrane potential oscillation in axonal conduction block induced by high-frequency (kHz) biphasic stimulation (HFBS). APPROACH The model includes intracellular and extracellular sodium and potassium concentrations and ion pumps. First, the HFBS (1 kHz, 5.4 mA) was applied for a duration (59.4 seconds) long enough to produce an axonal conduction block after terminating the stimulation, i.e., a post-stimulation block. Then, the intensity of HFBS was reduced to a lower level for 4 seconds to determine if the axonal conduction block could be maintained. MAIN RESULTS The block duration was shortened from 1363 ms to 5 ms as the reduced HFBS intensity was increased from 0 mA to 4.1 mA. The block was maintained for the entire tested period (4000 ms) if the reduced intensity was above 4.2 mA. At the low intensity (<4.2 mA) the membrane potential oscillation disrupted the post-stimulation block caused by the increased intracellular sodium concentration, while at the high intensity (>4.2 mA) the membrane potential oscillation was strong enough to maintain the block and further increased the intracellular sodium concentration. SIGNIFICANCE This study indicates a possibility to develop a new nerve block method to reduce the HFBS intensity, which can extend the battery life for an implantable nerve stimulator in clinical applications to block pain of peripheral origin.
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Affiliation(s)
- Yihua Zhong
- University of Pittsburgh, Department of Urology, 700 Kaufmann Building, Pittsburgh, Pennsylvania, 15261, UNITED STATES
| | - Xu Zhang
- Capital Medical University, School of Biomedical Engineering and Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, China, Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University,100069, Beijing, China, Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Capital Medical University, Beijing 100069, China, Beijing, 100054, CHINA
| | - Jonathan Beckel
- University of Pittsburgh, 4200 Fifth Ave, Pittsburgh, Pittsburgh, Pennsylvania, 15261, UNITED STATES
| | - William C de Groat
- University of Pittsburgh School of Medicine, 4200 Fifth Ave, Pittsburgh,, Pittsburgh, Pennsylvania, 15261, UNITED STATES
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh, 700 Kaufmann Building, Pittsburgh, PA 15213, USA, Pittsburgh, Pennsylvania, 15261, UNITED STATES
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Álvarez DMC, Serrano-Muñoz D, Fernández-Pérez JJ, Gómez-Soriano J, Avendaño-Coy J. Effect of Percutaneous Electric Stimulation with High-Frequency Alternating Currents on the Sensory-Motor System of Healthy Volunteers: A Double-Blind Randomized Controlled Study. J Clin Med 2022; 11:jcm11071832. [PMID: 35407438 PMCID: PMC8999650 DOI: 10.3390/jcm11071832] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/17/2022] [Accepted: 03/24/2022] [Indexed: 02/05/2023] Open
Abstract
Former studies investigated the application of high-frequency alternating currents (HFAC) in humans for blocking the peripheral nervous system. The present trial aims to assess the effect of HFAC on the motor response, somatosensory thresholds, and peripheral nerve conduction when applied percutaneously using frequencies of 10 kHz and 20 kHz in healthy volunteers. A parallel, placebo-controlled, double-blind, randomized clinical trial was conducted. Ultrasound-guided HFAC at 10 kHz and 20 kHz and sham stimulation were delivered to the median nerve of 60 healthy volunteers for 20 min. The main assessed variables were the maximum isometric flexion strength (MFFS) of the index finger, myotonometry, pressure pain threshold (PPT), mechanical detection threshold (MDT), and sensory nerve action potential (SNAP). A decrease in the MFFS is observed immediately postintervention compared to baseline, both in the 10 kHz group (−8.5%; 95% CI −14.9 to −2.1) and the 20 kHz group (−12.0%; 95% CI −18.3 to −5.6). The between-group comparison of changes in MFFS show a greater reduction of −10.8% (95% CI −19.8 to −1.8) immediately postintervention in the 20 kHz compared to the sham stimulation group. The percutaneous stimulation applying 20 kHz HFAC to the median nerve produces a reversible postintervention reduction in strength with no adverse effects.
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Zhong Y, Wang J, Beckel J, de Groat WC, Tai C. High-frequency stimulation induces axonal conduction block without generating initial action potentials. J Comput Neurosci 2021; 50:203-215. [PMID: 34800252 PMCID: PMC9035068 DOI: 10.1007/s10827-021-00806-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 11/05/2021] [Accepted: 11/17/2021] [Indexed: 10/19/2022]
Abstract
The purpose of this modeling study is to develop a novel method to block nerve conduction by high frequency biphasic stimulation (HFBS) without generating initial action potentials. An axonal conduction model including both ion concentrations and membrane ion pumps is used to analyze the axonal response to 1 kHz HFBS. The intensity of HFBS is increased in multiple steps while maintaining the intensity at a sub-threshold level to avoid generating an action potential. Axonal conduction block by HFBS is defined as the failure of action potential propagation at the site of HFBS. The simulation analysis shows that step-increases in sub-threshold intensity during HFBS can successfully block axonal conduction without generating an initial response because the excitation threshold of the axon can be gradually increased by the sub-threshold HFBS. The mechanisms underlying the increase in excitation threshold involve changes in intracellular and extracellular sodium and potassium concentration, change in the resting potential, partial inactivation of the sodium channel and partial activation of the potassium channel by HFBS. When the excitation threshold reaches a sufficient level, an acute block occurs first and after additional sub-threshold HFBS it is followed by a post-stimulation block. This study indicates that step-increases in sub-threshold HFBS intensity induces a gradual increase in axonal excitation threshold that may allow HFBS to block nerve conduction without generating an initial response. If this finding is proven to be true in human, it will significantly impact clinical applications of HFBS to treat chronic pain.
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Affiliation(s)
- Yihua Zhong
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA.,School of Biomedical Engineering, Capital Medical University, Beijing, P.R. China
| | - Jicheng Wang
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jonathan Beckel
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - William C de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA. .,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA. .,Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
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5
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Cai H, Morgan T, Pace N, Shen B, Wang J, Roppolo JR, Horlen K, Khanwilkar P, Groat WC, Tai C. Low pressure voiding induced by a novel implantable pudendal nerve stimulator. Neurourol Urodyn 2019; 38:1241-1249. [DOI: 10.1002/nau.23994] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 02/01/2019] [Accepted: 03/18/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Haotian Cai
- Department of Urology University of Pittsburgh Pittsburgh Pennsylvania
- School of Health and Rehabilitation Science University of Pittsburgh Pittsburgh Pennsylvania
| | - Tara Morgan
- Department of Urology University of Pittsburgh Pittsburgh Pennsylvania
| | - Natalie Pace
- Department of Urology University of Pittsburgh Pittsburgh Pennsylvania
| | - Bing Shen
- Department of Urology University of Pittsburgh Pittsburgh Pennsylvania
| | - Jicheng Wang
- Department of Urology University of Pittsburgh Pittsburgh Pennsylvania
| | - James R. Roppolo
- Department of Pharmacology and Chemical Biology University of Pittsburgh Pittsburgh Pennsylvania
| | | | | | - William C. Groat
- Department of Pharmacology and Chemical Biology University of Pittsburgh Pittsburgh Pennsylvania
| | - Changfeng Tai
- Department of Urology University of Pittsburgh Pittsburgh Pennsylvania
- Department of Pharmacology and Chemical Biology University of Pittsburgh Pittsburgh Pennsylvania
- Department of Bioengineering University of Pittsburgh Pittsburgh Pennsylvania
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Lee YJ, Eom KS, Kim HY, Ahn KH, Lee SH. Uterosacral Nerve Stimulation via Cuff Electrode: A Preliminary Animal Study for Potential Application to Treatment of Preterm Labor. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2018:4186-4189. [PMID: 30441278 DOI: 10.1109/embc.2018.8513276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Preterm labor occurs in about 12% of all pregnancies, accounting for at least 75% of neonatal deaths. The neonatal outcomes depend on mainly the gestational age at delivery. The lower the gestational age, the higher the risk of morbidity and mortality. The management of preterm labor involves early detection of high-risk women, prevention and treatment. In this study, the feasibility and stability of implantable cuff electrodes detection and inhibition of uterine contractions for preterm labor treatment were investigated by in-vivo mouse test. In order to check functionality of implanted electrodes, acute in-vivo test at mouse uterosacral ligament was performed by using cuff electrode which stimulate and record nerve activity. As results, the electrical stimulation via a stimulating cuff electrode at mouse uterosacral ligament was properly applied and nerve fiber's signal was recorded via the recording electrode. In addition, the implanted cuff electrodes could obtain stable recording signal to the periodic electrical stimulation for 7 weeks.
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Song KI, Park SE, Lee S, Kim H, Lee SH, Youn I. Compact Optical Nerve Cuff Electrode for Simultaneous Neural Activity Monitoring and Optogenetic Stimulation of Peripheral Nerves. Sci Rep 2018; 8:15630. [PMID: 30353118 PMCID: PMC6199280 DOI: 10.1038/s41598-018-33695-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 10/03/2018] [Indexed: 01/05/2023] Open
Abstract
Optogenetic stimulation of the peripheral nervous system is a novel approach to motor control, somatosensory transduction, and pain processing. Various optical stimulation tools have been developed for optogenetic stimulation using optical fibers and light-emitting diodes positioned on the peripheral nerve. However, these tools require additional sensors to monitor the limb or muscle status. We present herein a novel optical nerve cuff electrode that uses a single cuff electrode to conduct to simultaneously monitor neural activity and optogenetic stimulation of the peripheral nerve. The proposed optical nerve cuff electrode is designed with a polydimethylsiloxane substrate, on which electrodes can be positioned to record neural activity. We confirm that the illumination intensity and the electrical properties of the optical nerve cuff electrode are suitable for optical stimulation with simultaneous neural activity monitoring in Thy1::ChR2 transgenic mice. With the proposed electrode, the limb status is monitored with continuous streaming signals during the optical stimulation of anesthetized and moving animals. In conclusion, this optical nerve cuff electrode provides a new optical modulation tool for peripheral nervous system studies.
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Affiliation(s)
- Kang-Il Song
- Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Sunghee Estelle Park
- Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea.,Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Seul Lee
- Department of Dentistry, Graduate School, Kyunghee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Hyungmin Kim
- Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Soo Hyun Lee
- Brain Science Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Inchan Youn
- Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea. .,KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul, 02447, Republic of Korea.
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8
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Avendano-Coy J, Serrano-Munoz D, Taylor J, Goicoechea-Garcia C, Gomez-Soriano J. Peripheral Nerve Conduction Block by High-Frequency Alternating Currents: A Systematic Review. IEEE Trans Neural Syst Rehabil Eng 2018; 26:1131-1140. [DOI: 10.1109/tnsre.2018.2833141] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Yang G, Wang J, Shen B, Roppolo JR, de Groat WC, Tai C. Pudendal nerve stimulation and block by a wireless-controlled implantable stimulator in cats. Neuromodulation 2013; 17:490-6; discussion 496. [PMID: 24320615 DOI: 10.1111/ner.12136] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 09/20/2013] [Accepted: 10/25/2013] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The study aims to determine the functionality of a wireless-controlled implantable stimulator designed for stimulation and block of the pudendal nerve. MATERIALS AND METHODS In five cats under α-chloralose anesthesia, the stimulator was implanted underneath the skin on the left side in the lower back along the sacral spine. Two tripolar cuff electrodes were implanted bilaterally on the pudendal nerves in addition to one bipolar cuff electrode that was implanted on the left side central to the tripolar cuff electrode. The stimulator provided high-frequency (5-20 kHz) biphasic stimulation waveforms to the two tripolar electrodes and low-frequency (1-100 Hz) rectangular pulses to the bipolar electrode. Bladder and urethral pressures were measured to determine the effects of pudendal nerve stimulation (PNS) or block. RESULTS The maximal (70-100 cmH2O) urethral pressure generated by 20-Hz PNS applied via the bipolar electrode was completely eliminated by the pudendal nerve block induced by the high-frequency stimulation (6-15 kHz, 6-10 V) applied via the two tripolar electrodes. In a partially filled bladder, 20-30 Hz PNS (2-8 V, 0.2 ms) but not 5 Hz stimulation applied via the bipolar electrode elicited a large sustained bladder contraction (45.9 ± 13.4 to 52.0 ± 22 cmH2O). During cystometry, the 5 Hz PNS significantly (p < 0.05) increased bladder capacity to 176.5 ± 27.1% of control capacity. CONCLUSIONS The wireless-controlled implantable stimulator successfully generated the required waveforms for stimulation and block of pudendal nerve, which will be useful for restoring bladder functions after spinal cord injury.
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Affiliation(s)
- Guangning Yang
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Biomedical Engineering, Beijing Jiaotong University, China
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10
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Optical control of neuronal excitation and inhibition using a single opsin protein, ChR2. Sci Rep 2013; 3:3110. [PMID: 24173561 PMCID: PMC3813941 DOI: 10.1038/srep03110] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 10/14/2013] [Indexed: 12/11/2022] Open
Abstract
The effect of electrical stimulation on neuronal membrane potential is frequency dependent. Low frequency electrical stimulation can evoke action potentials, whereas high frequency stimulation can inhibit action potential transmission. Optical stimulation of channelrhodopsin-2 (ChR2) expressed in neuronal membranes can also excite action potentials. However, it is unknown whether optical stimulation of ChR2-expressing neurons produces a transition from excitation to inhibition with increasing light pulse frequencies. Here we report optical inhibition of motor neuron and muscle activity in vivo in the cooled sciatic nerves of Thy1-ChR2-EYFP mice. We also demonstrate all-optical single-wavelength control of neuronal excitation and inhibition without co-expression of inhibitory and excitatory opsins. This all-optical system is free from stimulation-induced electrical artifacts and thus provides a new approach to investigate mechanisms of high frequency inhibition in neuronal circuits in vivo and in vitro.
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Liu H, Zhu L, Sheng S, Sun L, Zhou H, Tang H, Qiu T. Post stimulus effects of high frequency biphasic electrical current on a fibre's conductibility in isolated frog nerves. J Neural Eng 2013; 10:036024. [PMID: 23676976 DOI: 10.1088/1741-2560/10/3/036024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE High frequency biphasic (HFB) electrical currents are widely used in nerve blocking studies. Their safety margins largely remain unknown and need to be investigated. APPROACH This study, exploring the post stimulus effects of HFB electrical currents on a nerve's conductibility, was performed on bullfrog sciatic nerves. Both compound action potentials (CAPs) and differential CAPs (DCAPs, i.e. control CAPs subtracted by CAPs following HFB currents) were obtained, and N1 and N2 components, which were the first and second upward components of DCAPs, were used for analyses of the effects introduced by HFB electrical stimulation. MAIN RESULTS First, HFB currents of 10 kHz at a completely blocking threshold were applied for 5 s. The maximum amplitudes and conducting velocities of the CAPs were significantly (P < 0.02) decreased within the observed period (60 s) following HFB currents. The DCAPs displayed clear N1 and N2 components, demonstrating respectively the losses of the fibres' normal conductibility and the appearances of new delayed conductions. Decreases of N1 amplitudes along time, regarded as the recovery of the nerve's conductibility, exhibited two distinct phases: a fast one lasting several seconds and a slow one lasting longer than 5 min. Further tests showed a linear relationship between the HFB stimulation durations and recovering periods of N1 amplitudes. Supra-threshold blocking did not cause higher N1 amplitudes. SIGNIFICANCE This study indicates that HFB electrical currents lead to long lasting post stimulus reduction of a nerve's conductibility, which might relate to potential nerve injuries. A possible mechanism, focusing on changes in intracellular and periaxonal ionic concentrations, was proposed to underlie the reduction of the nerve's conductibility and potential nerve injuries. Greater caution and stimulation protocols with greater safety margins should be explored when utilizing HFB electrical current to block nerve conductions.
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Affiliation(s)
- Hailong Liu
- Department of Biomedical Engineering, Dalian University of Technology, Dalian, Liaoning, People's Republic of China.
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Tai C, Guo D, Wang J, Roppolo JR, de Groat WC. Mechanism of conduction block in amphibian myelinated axon induced by biphasic electrical current at ultra-high frequency. J Comput Neurosci 2011; 31:615-23. [PMID: 21523417 DOI: 10.1007/s10827-011-0329-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 04/01/2011] [Accepted: 04/08/2011] [Indexed: 10/18/2022]
Abstract
The mechanism of axonal conduction block induced by ultra-high frequency (≥ 20 kHz) biphasic electrical current was investigated using a lumped circuit model of the amphibian myelinated axon based on Frankenhaeuser-Huxley (FH) equations. The ultra-high frequency stimulation produces constant activation of both sodium and potassium channels at the axonal node under the block electrode causing the axonal conduction block. This blocking mechanism is different from the mechanism when the stimulation frequency is between 4 kHz and 10 kHz, where only the potassium channel is constantly activated. The minimal stimulation intensity required to induce a conduction block increases as the stimulation frequency increases. The results from this simulation study are useful to guide future animal experiments to reveal the different mechanisms underlying nerve conduction block induced by high-frequency biphasic electrical current.
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Affiliation(s)
- Changfeng Tai
- Department of Urology, University of Pittsburgh, 700 Kaufmann Building, Pittsburgh, PA 15213, USA.
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TAI C, ROPPOLO JR. Bladder and Sphincter Control after Spinal Cord Injury. Low Urin Tract Symptoms 2009. [DOI: 10.1111/j.1757-5672.2009.00038.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Liu H, Roppolo JR, de Groat WC, Tai C. Modulation of axonal excitability by high-frequency biphasic electrical current. IEEE Trans Biomed Eng 2009; 56:2167-76. [PMID: 19389692 DOI: 10.1109/tbme.2009.2020296] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The modulation of axonal excitability by high-frequency biphasic (HFB) electrical current was analyzed using a lumped-circuit model of the myelinated axon based on Schwarz-Reid-Bostock (SRB) equations. The results show that axonal excitability could be either increased or decreased by HFB current depending on the current intensity. The increase of axonal excitability is due to the high level of sodium channel activation, whereas the activation of both fast and slow potassium channels plays an important role in decreasing axonal excitability. As the HFB current intensity increases, the location determining the axonal excitability changes from the nodes under the electrode within the "main lobe" region of the activating function to the nodes away from the electrode in the "side lobe" region of the activating function. This simulation study also shows that the modulation of axonal excitability by HFB electrical current could be potentially useful to selectively activate the small nerve fibers in a compound nerve trunk without activating the large fibers. Understanding how HFB electrical current modulates the axonal excitability will further elucidate the possible mechanisms underlying the nerve conduction block induced by HFB electrical current.
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Affiliation(s)
- Hailong Liu
- Department of Urology and Department of Pharmacology, University of Pittsburgh, Pittsburgh, PA 15261 USA
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15
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Tai C, Wang J, Roppolo JR, de Groat WC. Relationship between temperature and stimulation frequency in conduction block of amphibian myelinated axon. J Comput Neurosci 2008; 26:331-8. [PMID: 18839298 DOI: 10.1007/s10827-008-0115-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 09/02/2008] [Accepted: 09/12/2008] [Indexed: 11/25/2022]
Abstract
The temperature-frequency relationship in nerve conduction block induced by high-frequency, biphasic electrical current was investigated by computer simulation using an amphibian myelinated axon model based on Frankenhaeuser-Huxley (FH) equations. For an axon of diameter 10 microm, the minimal blocking frequency was changed from 6 to 3 kHz as the temperature was decreased from 37 degrees C to 15 degrees C. The maximal blocking temperature below which the axon could be blocked was increased from 22 degrees C to 37 degrees C as the stimulation frequency was increased from 4 to 8 kHz. The maximal blocking temperature was not influenced by axon diameter. Simulation analysis also revealed that activation of potassium channels might determine the temperature-frequency relationship. This study indicates that temperature might be one of the factors that cause the frequency discrepancy as reported in previous animal studies.
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Affiliation(s)
- Changfeng Tai
- Department of Urology, University of Pittsburgh, W1354 Biomedical Science Tower, Pittsburgh, PA 15261, USA.
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